Effect Of Radiotherapy On Survival Of Patients With Locally Advanced Gastric Cancer After D2 Radical Resection

Objective: To investigate the effect of radiotherapy on local control and long-term survival of patients with locally advanced gastric cancer after D2 radical resection,and to screen the clinicopathological factors related to survival and prognosis of patients.Methods: A total of 157 patients with locally advanced gastric cancer treated in the People’s Hospital of Guangxi Zhuang Autonomous Region from January 2011 to December2012 after D2 radical resection were collected for retrospective analysis.Postoperative radiotherapy group was set as postoperative radiotherapy group(n=75 cases).Control group without postoperative adjuvant radiotherapy(n=82 cases).Kaplan-Meier method was used for survival analysis and survival curve was drawn.Log-rank method was used to compare survival,recurrence and metastasis between the two groups.Prognostic factors affecting overall survival and disease-free survival were analyzed by univariate and multivariate analysis.Finally,subgroup analysis was conducted to determine the effects of postoperative radiotherapy on overall survival and disease-free survival of patients with locally advanced gastric cancer after D2 radical resection in different subgroups.Results: 1.By December 2017,the median follow-up time was 40 months.The 3-year overall survival rate was 66.0% vs 63.3% and the 5-year overall survival rate was 62.2% vs48.4% in the postoperative radiotherapy group and the control group(P=0.305),3-year and5-year disease-free survival rates were 80.2% vs 58.2% and 72.3% vs 50.5% in postoperative radiotherapy and control groups(P=0.007).2.Analysis of the recurrence and metastasis patterns showed that the local recurrence rates in the postoperative radiotherapy group and the control group were 8.0% vs18.3%(P=0.055),and the distant metastasis rates were 21.3% vs39%(P=0.019),respectively.The local recurrence rates and distant metastasis rates in the postoperative radiotherapy group were significantly lower than those in the control group(P<0.05).3.Subgroup analysis showed that patients with positive lymph nodes,stage N1-2 and III in postoperative radiotherapy group and control group had significantly improved disease-free survival rate(P<0.05),while there was no statistical difference in overall survival rate(P>0.05).4.Through univariate and multivariate prognostic analysis of overall survival rate and disease-free survival rate,univariate analysis showed that the survival prognosis of patients with locally advanced gastric cancer after D2 radical resection was related to the degree of tumor differentiation,the number of adjuvant chemotherapy cycles,T stage,N stage and TNM stage(P<0.05).Further multivariate analysis showed that,The number of adjuvant chemotherapy cycles and N stages were considered to be independent risk factors affecting overall survival(P<0.05).In addition,univariate analysis showed that the disease-free survival rate of patients with locally advanced gastric cancer after D2 radical surgery was related to the degree of tumor differentiation,the number of adjuvant chemotherapy cycles,T stage,N stage,and TNM stage(P<0.05).Further multivariate analysis showed that the number of adjuvant chemotherapy cycles was considered to be an influencing factor for disease-free survival rate(P<0.05).Conclusions: Postoperative radiotherapy can reduce the local recurrence rate and distant metastasis rate,improve disease-free survival rate and have no significant effect on overall survival rate compared with the group without radiotherapy after D2 radical resection for locally advanced gastric cancer.Subgroup analysis showed that postoperative radiotherapy improved disease-free survival in node-positive patients and stage III patients,and N1-2significantly affected disease-free survival.The number of adjuvant chemotherapy cycles and N stage were independent risk factors for patients’ recurrence survival(both P values were less than 0.05).